Many electronic devices include security features to prevent unauthorized access. For example, an electronic device can include a biometric sensor configured to establish a user's identity by determining whether obtained biometric data matches known biometric data of an authorized user. A fingerprint imaging system is one example of a biometric sensor.
In many cases, the performance of a biometric sensor may be affected by the precision with which biometric data can be detected. Although increased precision may lead to improved security for the electronic device, it may also result in a physical reduction in the size of one or more components of the sensor. For example, a high-precision fingerprint imaging system may require smaller imaging sensors than low-precision imaging systems.
Furthermore, the quality of a signal obtained from physically smaller components is often negatively affected by the components' smaller size. For example, small imaging sensors may detect less image information than large imaging sensors, generating lower-amplitude signals that may be more sensitive to interference. In other cases, small imaging sensors may be more susceptible to signal distortion from environmental conditions (e.g., temperature, pressure, humidity, and so on) than larger imaging sensors.
To account for the lower signal quality that may be associated with smaller components, many high-precision biometric sensors require close physical proximity (e.g., less than a millimeter) to a user in order to obtain a signal of sufficient quality. In other cases, biometric sensors may require advanced signal processing capability, which may undesirably increase power consumption and processing delays of the system.
As a result, high-precision biometric sensors are often challenging to include within the housing of an electronic device. For example, a biometric sensor positioned within a millimeter of the exterior of a housing may be at substantial risk of impact damage. In other examples, advanced signal processing capability may not be conveniently implemented by an electronic device with limited power and/or processing resources.
Accordingly, there may be a present need for improved high-precision biometric sensors.